CN110873192B

CN110873192B - Fluoroplastic butterfly valve structure

Info

Publication number: CN110873192B
Application number: CN201910440825.8A
Authority: CN
Inventors: 简焕然; 陈柏文
Original assignee: Bueno Tech Co Ltd
Current assignee: Bueno Tech Co Ltd
Priority date: 2018-09-04
Filing date: 2019-05-24
Publication date: 2021-07-16
Anticipated expiration: 2039-05-24
Also published as: TW202010964A; JP6928329B2; US20200072359A1; TWI677638B; JP2020037996A; DE102019116175A1; CN110873192A; US11035474B2

Abstract

The invention provides a fluoroplastic butterfly valve structure, which comprises a valve body, a butterfly plate, a lining and a back ring, wherein the butterfly plate is arranged on the valve body; the butterfly plate is of a disc structure and comprises a metal butterfly plate positioned inside and a fluoroplastic package wrapping the metal butterfly plate outside, the butterfly plate is provided with a valve shaft, the part connected with the valve shaft is provided with two bulges, and the section of the butterfly plate is of a plate-shaped or conical surface structure; the valve shaft is mounted in the shaft hole of the valve body, so that the butterfly plate can rotate to regulate flow or open and close the valve; the inner peripheral surface of the valve body is provided with a back ring and a fluoroplastic lining, the outer edge of the butterfly plate and the inner surface of the lining perform a tightening function of interference compression joint sealing, and the tightening amount is provided with deformation and required pressing pressure by a high-temperature resistant rubber back ring between the inner peripheral surface of the valve body and the lining, so that the operation requirement of high-temperature and high-pressure fluid at 200 ℃ can be met.

Description

Fluoroplastic butterfly valve structure

Technical Field

The invention relates to a fluoroplastic butterfly valve structure, in particular to a symmetrical butterfly valve structure provided with a corrosion-resistant and high-temperature-resistant fluoroplastic lining, wherein a butterfly plate of the symmetrical butterfly valve structure is provided with an internal metal butterfly plate which is encapsulated by an external fluoroplastic, so that the sealing mechanism of the outer edge of the butterfly plate is improved, the torsion requirement of a valve shaft is reduced, the service life of the fluoroplastic lining is prolonged, the pressure and temperature tolerance capacity during sealing closing is improved, the outer edge of the butterfly plate can slide in an interference manner during closing, and compression sealing is achieved during complete closing, so that the specifications of a special-purpose butterfly valve can be met, for example:

corrosive liquid: conveying hydrofluoric acid, hydrochloric acid, sulfuric acid and other fluids;

maximum temperature: special use ≦ 200 ℃;

the highest pressure: special use ≦ 3kg @200 ℃.

Background

Referring to fig. 7A, 7B, 7C and 7D, a fluoroplastic symmetric butterfly valve 9 of the prior art is shown, which is used for conveying clean water and general temperature corrosive liquid; the fluoroplastic butterfly valve 9 is made of fluoroplastic with high flexibility assisted by low hardness and high elasticity of rubber, and is composed of a valve body 91, a butterfly plate 92, a liner 93, a back ring 94, a valve shaft 95, and the like.

The valve body 91 is formed by dividing horizontally into two semi-circular valve bodies, the upper valve body and the lower valve body are fastened and locked into a whole by two bolts, the inner circumferential surface 911 of the valve body 91 is provided with a groove 912 for mounting a back ring 94, not shown, and the inner circumferential surface 911 is also used for mounting a liner 93, and the two-piece valve body is provided with an upper shaft hole part 913 and a lower shaft hole part 914, respectively.

As shown in fig. 7C, the back ring 94 is made of rubber and is disposed in the annular groove 912 of the inner circumferential surface 911 and between the tubular portions 931, so that the back ring 94 can compensate for the lack of elasticity of the fluoroplastic and provide a high amount of deformation and reduce torque requirements, and provide deformation support for the inner liner surface 933 and pressure sealing capability of the outer edges 922 and the inner liner surface 933. The material of the backing ring 94 is temperature resistant, and the temperature resistance of general rubber is less than or equal to 120 ℃, the temperature resistance of fluororubber is less than or equal to 180 ℃, and the temperature resistance of silicone rubber is less than or equal to 260 ℃ (500 DEG F).

As shown in fig. 7D, the liner 93 has a tubular portion 931 and radial flanges 932 at both ends thereof, which are used as sealing surfaces for pipe connection and reduce the shrinkage deformation of the tubular portion 931 after high temperature is experienced by the support of the valve body 91, the butterfly outer edge 922 is pressed against the inner diameter surface of the tubular portion 931 supported by the valve body 91 and the back ring 94 when the valve is closed, hereinafter referred to as a liner inner surface 933, the back ring 94 provides the required strength for sealing the most tubular portion 931 with a thin structure to seal the fluid flow and withstand the pressure and temperature of the fluid, the tubular portion 931 is provided with a horizontal sealing plane 632 at each end in the diameter direction, the thickness of the horizontal sealing plane 632 covers the planar structure of both the inner diameter and the outer diameter of the tubular portion 931, the diameter distance between the two horizontal sealing planes 632 is smaller than the inner diameter of the tubular portion 931, and the thickness of the sealing plane 632 is larger than the thickness of the tubular portion 931, the joints between the two sides of the sealing plane 632 and the inner diameter surface of the liner are respectively provided with a connecting angle 633, and the connecting angle 633 is formed by circular arcs and is used for connecting structures with different thicknesses; a shaft hole surface 634 and a shaft hole 937 are provided in the seal plane 632 for mounting the valve shaft 95, not shown, so that the butterfly plate 92 can be rotated to adjust the flow rate or open/close the valve, not shown.

As shown in fig. 7C and 7D, the inner diameter of the rubber back ring 94 is equal to the inner diameter of the inner circumferential surface 23 and equal to the outer diameter of the tubular portion 31, but during the manufacturing process, the outer diameter of the tubular portion 931 is slightly smaller than the inner diameter of the inner circumferential surface 911 due to shrinkage and deformation during the manufacturing process, and the inner diameter of the rubber back ring 94 is also slightly smaller than the inner diameter of the inner circumferential surface 911 due to shrinkage and deformation during the manufacturing process, that is, the inner liner inner surface 933 is slightly convex due to deformation after assembly to reduce the inner radius, so that the inner diameter cross-section of the inner liner 933 is in the shape of the cross-sectional curve 66a and has the protrusion height 66b (h), so that the radius of the flap plate side-wings 921 is larger than the inner radius of the inner liner inner surface 933 to increase the tightening amount 65 (epsilon), and when the two-piece valve body 92 is fastened by two bolts in the prior art, the valve body 92 is also tightened, the rubber back ring 94 and the, because the valve body 91 also reserves tolerance margins and tight spaces.

Referring to fig. 7A and 7B, the butterfly plate 92 is shaped like a disk, and the cross section of each of the two side wings of the butterfly plate 92, hereinafter referred to as the butterfly plate side wing 921, is shaped like a plate, and hereinafter referred to as the band seal butterfly plate 92B, and the seal structure is referred to as the band seal 62, and the outer edge 922 of the butterfly plate forms a ring-shaped surface 923; the section of the sealing structure is a tapered section, which is hereinafter referred to as a linear sealing butterfly plate 92a, the sealing structure is referred to as a linear sealing 61, and the outer edge 922 of the butterfly plate is a conical curved surface 924; the outer diameter is slightly larger than the inner diameter of the lining 93, and the difference of the radii is the packing amount 65 (epsilon); the butterfly plate 92 can bear the torque 79(T) transmitted by the valve shaft 95 to open and close the butterfly valve 9, the torque 79(T) is originated from the original shaft sealing required torque, and when the butterfly plate 92 is opened and closed, the outer edge 922 of the butterfly plate can perform tight sliding on the inner lining inner surface 933, so that friction torque 794(Tf), hereinafter referred to as interference sliding 7, and fluid torque 792(Th) and static pressure torque 793(Tp), including pipeline static pressure 82(Ps), are generated, as shown in fig. 7E and 7F; two ends of the butterfly plate outer edge 922 in the diameter direction are respectively provided with a horizontal sealing end face 635, the sealing end face 635 is opposite to the horizontal sealing plane 632 of the lining 93, and a cut corner 636 is respectively arranged at the connecting part of two sides of the sealing end face 635 and the ring curved surface 923, the cut corner 636 is formed by an arc, and the cut corner 636 is sealed opposite to the connecting corner 633 of the sealing plane 632; the sealing end face 635 and the sealing plane 632 are axially and vertically clamped and sealed, and the vertical sealing is converted into radial sealing at the cut corner 636 and the connecting corner 633, but the thickness of the sealing plane 632 and the thickness of the tubular part 931 are different, and special treatment is needed to provide clamping sealing so as to prevent pressure leakage; the tightening of the outer edge 922 of the butterfly plate against the inner surface 933 of the liner when the valve is closed to form the band seal 62 or the linear seal 61, the pressing of the shaft bore surface 634 against the shaft sealing surface 637, and the sealing of the corner 633 against the corner 636, these successive tightening surfaces forming the so-called sealing surface 6; a protruding structure, which is referred to as a butterfly plate protrusion 927 hereinafter, is respectively arranged on the two sealing end surfaces 635, a shaft hole 928 and a shaft sealing surface 637 are arranged in the center of the butterfly plate protrusion 927, the shaft hole 928 is used for mounting a valve shaft 95, the shaft sealing surface 637 is used for pressure-welding and sealing with the shaft hole surface 634, and the shaft sealing surface 637 is connected with a butterfly plate outer edge 922 to form a complete sealing surface 6; generally, the butterfly plate protrusion 927 is also the portion of the butterfly plate 92 with the largest thickness, and some designs connect the two butterfly plate protrusions 927 by a diameter connection 929, as shown in fig. 7B, and there are designs without such a design as shown in fig. 7A, and the design of the diameter connection 929 and the butterfly plate protrusion 927 will enhance the structural strength but reduce the area of the flow passage 8 and greatly reduce the flow performance, i.e., reduce the Cv value, as shown in fig. 7F.

Referring to FIG. 7A, the butterfly plate 92 has a turning radius Ra at a section a-a near the valve shaft 95, a turning radius Rc at a section c-c near the maximum diameter perpendicular to the horizontal direction of the valve shaft, and a turning radius Rb at a section b-b between the two.

Referring to FIG. 7E, the fluid torque 792(Th) of the valve shaft is more pronounced in the large butterfly valve because two slit flow passages 81, one converging flow passage 815 and one diverging flow passage 814 are formed between the inner liner 93 and the two sides of the butterfly plate side 921 during closing, and the fluid flow line 811 creates an asymmetric flow return area 812 and cavitation, which causes the two sides of the butterfly plate side 921 to experience different pressures and results in the fluid torque 792 (Th).

Referring to fig. 8A, 8Aii, 8Aiii and 8D, a band-shaped sealing butterfly plate 92b, 9A, 9Aii, 9Aiii and 9D, a linear sealing butterfly plate 92a, the butterfly plate 92 being located on a 0-degree center line when fully open, the butterfly plate 92 being located on a 90-degree center line when fully closed, when the butterfly plate 92 is turned from fully open to closed, a cross-sectional a-a position of a cross-section of the butterfly plate side 921 first contacts the rubber lining 93, a cross-sectional b-b position and a cross-sectional c-c position subsequently contact successively, hereinafter referred to as contact point 72, and contact angles of different butterfly plate shapes are different, and a line connecting the contact point 72 and a rotation axis of the valve shaft 95 forms an angle with the 90-degree center line, hereinafter referred to as contact angle 71(θ); under the same tightening amount 65 (epsilon), the contact angle 71 (theta) with the maximum value on the section a-a, the contact angle 71 (theta) with the order of b-b and the contact angle 71 (theta) with the minimum value on the section c-c are respectively realized, because the contact point 72 on the section a-a is the longest from the axis center, the contact point 72 on the section b-b is the next from the axis center and the contact point 72 on the section c-c is the shortest from the axis center; fig. 8D and 9D show that, at the section a-a, two sides of the annular curved surface 923 of the band-shaped sealing butterfly plate 92b have corner edges, which are formed by rounded corners with small curvature radius, hereinafter referred to as butterfly plate corner edges 923a, the butterfly plate corner edges 923a contact the inner liner surface 933 first during rotation, and the conical curved surface 924 of the linear sealing butterfly plate 92a contacts the inner liner surface 933; regarding the size of the contact angle 71(θ), the band-shaped seal butterfly 92b is larger than the linear seal butterfly 92a at each cross-sectional position, and the larger the contact angle 71(θ) is, the longer the distance representing the sliding interference 7 is, the larger the deformation of the liner inner surface 933 is.

As shown in fig. 8B and fig. 9B, when fully closed, the outer radius of the packing 65 (epsilon) from the butterfly plate 92 is larger than the difference value of the inner radius of the lining 93, the compression ratio of the lining 93 is equal to the ratio of the packing 65 (epsilon) to the thickness 941(s4) of the back ring 94, the value of the compression ratio is different according to the pressure resistance requirement and the hardness of the material, the higher the compression ratio is, the shorter the service life of the lining 93 is, and the compression ratio is in the range of 15% -25%.

Referring to fig. 8C and 9C, if a 3-inch diameter butterfly valve is used as an example, the thickness of the metal plate 92C at the outer edge 922 of the conventional band-shaped sealing butterfly plate 92b with the same diameter is 5mm, the radius of curvature of the corner edge 923a is 0.5mm, and the sealing width is 4mm, as shown in fig. 8C; the thickness of the metal plate 92C of the outer edge 922 of the existing linear sealing butterfly plate 92a with the same caliber is 2mm, and the sealing width is 2mm, as shown in fig. 9C; the butterfly plate 92 is not completely closed in the correct position and is at risk of static pressure leakage.

When the outer edge 922 of the band-shaped sealing butterfly plate 92B is pressed against the inner surface 933 of the liner, the tightening amount 65 (epsilon) and the sealing width 63(B) are higher, the pipeline static pressure 82(Ps) is higher as the larger the pressure, and when the outer edge 922 of the butterfly plate 92 is the annular curved surface 923, as shown in fig. 8C, the pressing effect of high-temperature and high-pressure resistance can be also borne when the outer edge 922 of the butterfly plate 92 is pressed against the inner surface 933 of the liner, such as the sealing width 63(B) being larger than or equal to 4mm, for example, a 3-inch butterfly valve is required, the outer edge 922 of the metal butterfly plate 92C inside the butterfly plate 92 does not intensively tighten the fluoroplastic package 69 to generate a large amount of package deformation 69a, and the liner deformation 68 (delta) generated by the inner surface 933 of the liner is smaller. When the outer edge 922 of the butterfly plate is a conical curved surface 924, as shown in fig. 9C, when the butterfly plate is pressed against the inner surface 933 of the liner, a sealing effect with a small sealing width 63(B), a high pressing pressure 64(P), and a high pressing amount 65 (epsilon) is desired, for example, the sealing width 63(B) ≦ 3mm, taking a 3-inch butterfly valve as an example, the narrow outer edge 922 of the metal butterfly plate 92C inside the butterfly plate 92 will intensively press the fluoroplastic package 69 to generate a large amount of package deformation 69a, and the liner deformation 68 (delta) generated by the inner surface 933 of the liner will be relatively large, so that it can be clearly seen that the width of the sealing surface 6 of the linear seal 61 is smaller than that of the strip-shaped seal 62.

Referring to fig. 9C, when the butterfly plate 92 is not closed correctly, the tightening amount 65 (e) and the sealing width 63(B) representing the outer edge 922 of the butterfly plate are insufficient and leakage is likely to occur, and especially the sealing width 63(B) of the linear seal 61 is insufficient, the prior art design strategy is to make the outer diameter of the butterfly plate 92 no longer be a true circle but approximate an ellipse at the C-C cross-sectional position, and locally increase the tightening amount 65 (e) at the C-C cross-sectional position to avoid leakage when the butterfly plate is closed incorrectly, but increase the valve shaft torque 79(T) requirement because the friction force 75(F) is also increased during the closing process.

As shown in fig. 8E, when the sliding interference 7 is performed, the outer edge 922 of the butterfly plate 92 and the contact surface of the liner deformation 68(δ) form a sliding surface, and also form a sliding included angle 74(ψ), and the sliding included angle 74(ψ) is formed by the tangent of the sliding surface and the tangent of the inner surface of the liner perpendicular to the valve axis; the small corner of the corner edge 923a of the band-shaped sealing butterfly plate 92b forms a sliding interface with the contact surface of the liner deformation 68(δ), the material of the inner liner surface 933 on the rear side of the outer edge 922 of the butterfly plate is under tension, the inner liner surface 933 on the front side is under friction 75(F) and extrudes the material to generate the convex liner deformation 68(δ), the outer edge of the metal butterfly plate 92c is under tension and extrusion to the fluoroplastic package 69 to generate the package deformation 69a by applying the friction 75(F), generally, the prior art leaves a connecting hole 513 on the metal butterfly plate 92c to strengthen the structural strength of the fluoroplastic package 69 to increase the service life, which is not shown.

As shown in fig. 9E, in the interference sliding 7 of the linear seal 61 in the section a-a during the closing process, the conical curved surface 924 slides forward at a sliding angle 74(ψ) larger than that of the band seal, that is, the conical curved surface 924 of the outer edge 922 of the butterfly plate applies a friction force 75(F) to press the inner surface 933 of the liner, and forms a pressing recess at the pressing position and pushes the material to bulge forward to form the liner deformation 68(δ), the material on the rear side bears more tension, and the outer edge of the metal butterfly plate 92c applies a larger friction force 75(F) to press and stretch the fluoroplastic package 69 to generate more package deformation 69a, so that the service life of the fluoroplastic package 69 becomes shorter.

As shown in fig. 8E and 9E, during the closing process, the butterfly plate 92 performs an interference sliding 7 on the liner 93, and continuously receives the frictional torque 794(Tf) generated by the frictional force 75(F) until the liner is completely closed; the hydrostatic torque 793(Tp) of the valve shaft comes from the fact that when the butterfly valve 9 is closed but the butterfly plate 92 is not completely closed, the hydrostatic torque 793(Tp) is generated because the line static pressure starts to be applied to the two side butterfly plate wings 921, and the rotation direction 791 and the pressure application direction are in the forward direction and the reverse direction.

Comparing fig. 8E and fig. 9E, the larger the tightening amount 65 (epsilon), and the larger the sliding angle 74 (psi), or fig. 8B and fig. 9B, the more likely a large amount of material deformation occurs; the larger the contact angle 71 (theta) of the band seal, the longer the sliding distance, the more material is subject to deformation and creep risk; at the same amount of tightening 65 (epsilon), the larger the sliding angle 74 (psi) of the linear seal 61, which means that a large amount of material deformation is concentrated in a small area, and material creep is likely to occur to impair the service life.

The following generalizes the above-listed problems of the prior art and the satisfaction of the requirements of the special specifications to the following problems:

problem 1: the higher the material deformation, the lining deformation 68 (delta) and the packaging deformation 69a, the better the sealing capability is, the better the static pressure 82(Ps) of the pipeline is born, but the creep easily occurs, the high torque is also needed, the interference sliding 7 during the rotation is not beneficial, and the service life of the butterfly valve is reduced particularly at high temperature; the belt-shaped seal 62 achieves the sealing effect of high pressure resistance and high temperature resistance by a larger sealing width 63(B), a lower compression pressure 64(p) and a lower tightening amount 65 (epsilon); the linear seal 61 achieves a high-pressure-resistant sealing effect with a small sealing width 63(B), a high pressure-bonding pressure 64(p), and a high packing amount 65 (epsilon), but is prone to creep and is not good for high-temperature resistance.

Problem 2: the contact angle 71 (theta) of the belt-shaped seal 62 at the section a-a of the interference sliding mechanism 7 is larger, the sliding distance is longer, the liner is deformed more by 68 (delta), the wear and creep are easy to occur at the section a-a, the leakage risk is increased, and the service life of the butterfly valve is shortened; the contact angle 71(θ) of the linear seal 61 at all cross-sectional positions is the smallest but the sliding angle 74(ψ) is the largest, and at high temperature or high packing 65(ε), the fluoroplastic package 69 and the liner inner surface 933 will undergo relatively more liner deformation 68(δ), package deformation 69a, and friction 75(F), so that the service life of the fluoroplastic package 69 and the liner inner surface 933 is shortened, and improvement of this problem becomes the most important issue.

Problem 3: a shaft bore surface, shaft bore surface 634 for coupling with shaft sealing surface 637 for a compression seal, the larger seal width 63(B) of shaft bore surface 634 will meet the sealing requirements, but the more sliding friction; the important problem is that the butterfly plate 92 can rotate without abrasion and creep caused by sliding friction; sealing of the corner 633 of the seal plane 632 with the cut-off corner 636 of the horizontal seal face 635 is also a problem.

Problem 4: the structure of the flow channel 8, the butterfly plate 92, the ring surface structure of the outer edge 922 of the butterfly plate, and the inner surface 933 structure of the lining will cause the performance of the butterfly valve to be reduced if the area of the flow channel 8 is reduced; the butterfly projection 927 of diameter link 929 occupies a larger flow area.

Problem 5: fluid torque (Th) and static torque (Tp), when two slit flow passages 81 are formed between two sides of the butterfly plate side wings 921 and the lining 93, the butterfly plate 92 will bear the maximum fluid torque 792(Th) because the rotating arm 73(R) is longest at the section c-c section position, and bear the maximum static torque 793(Tp) relatively when closing, and the minimum contact angle 71 (theta) will cause the tightening amount 65 (epsilon) to reduce the maximum and bear the maximum static torque 793(Tp) when incorrect closing; the prior art design is to increase the amount of packing 65(ε) at the section c-c section location to resist the hydrostatic torque, but also to increase the torque 79(T) requirement.

Problem 6: high temperature resistance, the liner 93 reduces the shrinkage of the tubular part 931 after high temperature by the support of the valve body 91, the high pressure and high temperature resistance is obtained by proper tightening amount 65 (epsilon) and proper interference sliding 7, so that the strength of the fluoroplastic material is not lost due to creep; at high temperatures the back ring 94 requires excess expansion space within the groove 912 to accommodate volume expansion; the high temperature and high pressure resistance of the band seal 62 may be relatively good; the linear seal 61 tends to fail to provide high temperature resistance.

Problem 7: the strength of the butterfly plate 92, using a thicker strip seal butterfly plate 92b rather than a diameter link 929 configuration, improves the stress concentration at the center of the butterfly plate, providing both higher strength and better flow performance.

The effectiveness of these prior art techniques will be reviewed in view of the problems and special specification requirements set forth above.

In reference to the first embodiment:

U.S. Pat. No. US3376014A, published in 1968, discloses a Replaceable butterfly valve device for use in a motor vehicle, which comprises a two-piece valve body, a fluoroplastic packing butterfly plate, a tubular liner and a back ring having flanges at both ends, the butterfly plate having a diameter connecting with a relatively large thickness and a shaft hole at both ends with high rigidity, and a wing of the butterfly plate having a thick flat plate structure, wherein when the liner has a cylindrical inner surface, the outer edge of the butterfly plate is pressed against the inner surface of the liner to form a band-shaped seal, thereby obtaining a sealing effect of 200psi or less, and when the inner surface of the cylindrical portion of the liner has an inwardly protruding trapezoidal cross section, a circumferential groove is provided at a middle position for accommodating the outer edge of the butterfly plate to form a groove-shaped band-shaped seal, thereby obtaining a sealing effect of 400 psi.

The design structure of this reference still has the following problems:

problem 1: the material deformation- -when the band seal is used, the sealing effect which is less than or equal to 200psi is obtained, and the material deformation is small, and the pressure resistance is also small; the inner surface of the liner with the convex trapezoid cross section and the grooves can obtain the sealing effect of more than 400psi, but the material has high deformation amount and cannot meet the requirements of torque and service life.

Problem 2: interference sliding, namely in the opening and closing process of the butterfly plate, the contact angle between the outer edge part and the inner surface of the inner lining with the convex trapezoidal section is reduced, interference sliding generated by deformation of a large amount of materials is generated between the outer edge part and the inner surface of the inner lining with the convex trapezoidal section, and the tightening amount rises quickly and also needs high torque.

Problem 3: shaft bore face-adding an O-ring to the shaft seal face as a countermeasure.

Problem 4: the inner surface of the lining with the flow channel-convex trapezoidal section can reduce the flow channel area, and the relative thickness of the butterfly plate bulge is large, so that the flow channel area is reduced.

Problem 5: fluid torque and hydrostatic torque- -not described.

Problem 6: high temperature resistance-the material volume of the convex trapezoidal cross section of the tubular portion is too large to avoid shrinkage after high temperature, and the structural strength of the back ring cannot be maintained at high temperature, thereby greatly reducing the high temperature resistance.

Problem 7: butterfly plate strength-with radial links and butterfly plate protrusions and thick plate-like cross-sections can provide high strength.

Reference scheme two:

1969 U.S. Pat. No. 3, 3447780A, PLASTIC RESIN LINED BUTTERFLY VALVE WITH IMPROVED SEALING ARRANGEMENTS, which is an innovative structure of the first reference, wherein the lining is designed to be thicker, the material in the middle of the tubular part is thinned to form a rectangular groove on the outer side for accommodating a back ring with a rectangular round-cornered cross section, and when the outer edge of the BUTTERFLY plate is pressed on the inner surface of the thinned lining, the high-elasticity back ring can completely support the inner surface of the lining to bear force without stretching deformation of the material, and the pressing surface is a small-width linear seal; sealing designs that also have grooves in the shaft sealing face and shaft bore face and use long cross-section O-rings with wedge-shaped ends can achieve sealing effects ≦ 500psi and 400 ° f.

The design structure of this reference still has the following problems:

problem 1: the material deformation-the outer edge of the butterfly plate with the conical section is a conical curved surface, which can provide linear sealing, can obtain the sealing effect less than or equal to 500psi and at the temperature of 400 DEG F, and can meet the requirement of low torque, but is limited by the different material thicknesses of the tubular part, the thin material structure of the sealing surface and the back ring which are not fixed by the groove of the valve body, the structure with different thicknesses under the use condition of 400 DEG F and long-term use, and the lack of data description on whether the requirements can be met in pressure resistance and service life.

Problem 2: the contact angle of the interference sliding-linear sealing is small, the interference sliding in the opening and closing process is not generated by a large amount of material deformation, and the higher torque requirement is not generated.

Problem 3: the shaft hole surface-the shaft sealing surface at the two ends of the butterfly plate and the corresponding shaft hole surface of the lining are respectively provided with an annular groove with a wedge-shaped cross section for accommodating an O-shaped ring made of fluoroplastic materials, and the cross section of the shaft hole surface is of an oval structure with two wedge-shaped ends, so that the sealing effect of pressure resistance less than or equal to 500psi and high temperature resistance of 400 DEG F can be obtained, but the connection and sealing mechanism of a linear sealing surface and the O-shaped ring is not specified, and whether the butterfly plate can be rotated to avoid abrasion or not is not specified, namely whether the service life meets the requirement or not is not specified.

Problem 4: the performance of the inner surface of the lining of the flow passage-cylinder section cannot be influenced, and the performance is influenced by the butterfly plate bulges with radial connection.

Problem 5: fluid torque and hydrostatic torque- -not described.

Problem 6: high temperature resistance-the rectangular groove on the outside of the tubular portion can increase with expansion or deformation of the back ring, which cannot be supported to maintain its strength, and greatly reduces the high temperature resistance at high temperatures.

Reference scheme three:

U.S. patent publication No. US3661171A, but BUTTERFLY VALVE, 1972, which is directed to improving the sealing function when the BUTTERFLY VALVE is fully closed, a symmetric BUTTERFLY VALVE device comprising a two-piece VALVE body, a fluoroplastic enveloping BUTTERFLY plate, an inner liner having flanges at both ends of a tubular portion, and a back ring, the BUTTERFLY plate having BUTTERFLY bosses at both ends thereof and a high rigidity flat plate structure provided with a VALVE shaft, the outer edge of the BUTTERFLY plate forming a band seal, the inner diameter surface of the VALVE body having a groove for receiving the back ring, the groove having a width equal to the thickness of the outer edge of the BUTTERFLY plate, the cylindrical portion having two radially parallel outwardly extending ribs on the outside thereof, the back ring having a circular cross section being received between the two ribs and then received in the groove on the inner diameter surface of the VALVE body, but the back ring having a radially projecting 0.036 inches on the inner surface of the inner liner at the central portion thereof in a concave and convex shape, the two side edges of the cylindrical, that is, the section of the cylinder part is less than 0.008 inch at the central part and is concave, when the outer edge of the butterfly plate is pressed on the inner surface of the lining, the back ring is flattened to smooth the inner surface of the lining, the interference sliding friction of the outer edge of the butterfly plate is reduced, and the torque cannot be increased and the butterfly valve cannot be abraded when rotating; the reference scheme is further modified, the outer edge of the butterfly plate is made into a conical curved surface to be capable of performing linear sealing, at the moment, the lining material can bear less tensile tension, creep generation and friction generation are reduced, the torque requirement is reduced, and the service life of the butterfly valve is further prolonged.

The design structure of this reference still has the following problems:

problem 1: the material deformation- -the inner surface of the cylindrical lining is provided with a plurality of bulges by a back ring, so that the original strip-shaped seal has the effect of approximate linear sealing, but the sealing width and the tightening amount are limited by the size of an O-ring, if a rubber O-ring with the section diameter of 10mm is used, the compression ratio of the compression tightening amount of about 0.036 inch (0.91mm) seems to be too low and is less than 10%, the data of citation data is lacked to support the effect, and when the outer edge of the butterfly plate is made into a conical curved surface, the compression area is reduced, and the pressure resistance is further reduced when the butterfly plate is linearly sealed.

Problem 2: interference sliding, namely the condition that the inner surface of the lining is slightly concave with 0.008 inch center and is provided with 0.036 inch bulge to approximate to linear sealing, the contact angle of the rotary butterfly plate is reduced, the torque requirement is low, so that the mutual interference sliding friction between the butterfly plate and the lining is reduced, and two ribs which are extended outwards in parallel in the radial direction are arranged on the outer side of the cylindrical part of the lining, so that the material deformation of the inner surface of the lining caused by interference sliding can be reduced, and the service life is prolonged.

Problem 3: the shaft hole surface is formed by adding an O-shaped ring structure to the back ring and additionally adding a cup-shaped part to increase the sealing of the shaft hole surface.

Problem 4: the inner surface of the flow channel and the lining is supported by a back ring by 0.036 inches, the influence of the reduction of the flow channel area is not obvious, the bulge of the butterfly plate does not occupy large flow channel area only at the shaft end, and the section of the butterfly plate is a flat plate without influencing the performance.

Problem 5: fluid torque and hydrostatic torque- -not described.

Problem 6: high temperature resistance-the silicone rubber back ring can have an expansion space at high temperature, and the outer edge of the cylindrical part of the lining is provided with two parallel ribs extending outwards in the radial direction, so that the high temperature resistance can be maintained.

Problem 7: the strength of the butterfly plate is that the butterfly plate is raised, the section of the butterfly plate is a flat plate, and the stress can be concentrated in the middle, so that the butterfly plate is suitable for medium-small size butterfly valves.

Reference scheme four:

japanese patent publication No. JPH1078143A, SEAT RING FOR BUTTERFLY VALVE, this reference is from Japanese patent publication No. JPS54103645U, BUTTERFLY VAlve, Japanese patent publication No. JPS55142169A, SEAT RING OF BUTTERFLY VALVE, two existing practical newly OF 1979, this reference aims at improving the controllability OF the linear degree OF low-flow rate when the VALVE is opened to a low degree, provide the annular inside lining that the BUTTERFLY plate must possess at the same time, can meet the requirement that the outer fringe OF the BUTTERFLY plate is pressed on two curved surfaces OF the inner surface OF the inside lining when rotating; the reference scheme is a rubber lining butterfly valve for normal temperature use, rubber has high deformation and high elasticity but cannot resist corrosion and high temperature, and a butterfly plate of the rubber lining butterfly valve can provide linear sealing by using the outer edge of the butterfly plate with a metal plate having a conical curved surface, but a method and a description for solving the problems still help to clear the problems from 1 to 7, and meanwhile, the prior art of the reference scheme can not meet the requirement that a fluoroplastic lining with higher hardness and strength is used under high temperature and high pressure; the inner surface of the lining of the reference case is an annular structure which is a curved surface protruding inwards and has a mountain-shaped cross section, the structure is called a mountain-shaped structure for short, the top end of the mountain-shaped structure is distributed annularly along the central line of the shaft hole surface of the lining on the inner surface of the lining, the mountain-shaped structure is divided into two semicircular structures by two shaft holes, and the two shaft hole surfaces can provide the shaft sealing surface of the outer edge of the butterfly plate for compression sealing; the section of the mountain-shaped structure takes the central line of the shaft hole surface as the center, two sections of symmetrical curves form two sections of inclined planes on two sides of the mountain-shaped structure, the mountain-shaped structure has different widths on different circumferential angles, namely two sections of curves with different lengths, the shaft hole end of the mountain-shaped structure on the a-a section has smaller width, the c-c section is far away from the shaft hole end and has larger width, and the sidelines of the two sections of inclined planes are mutually parallel, the mountain-shaped structure is used for improving the structural strength of the rubber lining, the butterfly plate can be pressed on the two sections of inclined planes on the inner surface of the lining when the valve is closed, namely the contact angle between the outer edge of the butterfly plate and the inner surface of the lining can be greatly reduced and is approximately equal, the friction of interference sliding is greatly reduced, the torque requirement can be reduced, and the service life; in taiwan patent publication No. TW496934B, Butterfly VALVE and thin plate ring in 2002, and japanese patent publication No. JP2003014139A, Butterfly VALVE in 2003, a raised ring structure with an asymmetric trapezoidal cross section on the inner surface of the liner is improved to enhance the sealing effect of the VALVE and reduce the torque requirement, which can be regarded as a further improvement of this reference, but such a rubber material structure is obviously not suitable for fluoroplastic materials, and the problem points are described as follows:

problem 1: material deformation-the butterfly plate can make a large amount of material deformation in a small area, the rubber lining can allow a linear seal of a large amount of material deformation, and the mountain-shaped section structure provides enough strength. If the fluoroplastic is used for manufacturing the mountain-shaped structure, the creep problem of deformation of a large amount of materials with small area cannot be borne, and when the outer edge of the butterfly plate packaged by the fluoroplastic is in compression joint, the narrow metal arc faces the packaging fluoroplastic in compression joint, the creep problem remained by compression joint sealing can also be caused, so that the packaging of the butterfly plate is invalid, and corrosive liquid can infiltrate.

Problem 2: when the interference sliding butterfly plate is used for linear sealing, the contact angle is relatively small, the width of the section of the a-a at the shaft hole end of the mountain-shaped structure on the inner surface of the lining is small, a relatively steep curved surface is formed, the tightening amount can rise rapidly, and high amount of deformation and high friction force can be generated. For the fluoroplastic lining, the butterfly plate must perform interference sliding on a steeper curved surface at the shaft hole end, fluoroplastic cannot bear deformation of a large amount of materials in a small area and high friction force generation, leakage risk near a valve shaft is large, and the service life of the butterfly valve is shortened; the fluoroplastic packaged by the butterfly plate and the fluoroplastic on the inner surface of the lining can bear high material deformation and creep, so that the packaging of the butterfly plate is invalid and corrosive liquid can permeate into the butterfly plate.

Problem 3: the shaft hole surface, namely the shaft sealing surface at the outer edge of the butterfly plate, has large-area interference compression joint sealing on the shaft hole surface, and the rubber material can meet the requirement that the butterfly plate cannot be abraded and creep caused by interference sliding friction under rotation. The fluoroplastic lining must be designed additionally on the shaft sealing surface and the shaft hole surface, and the large-area compression joint can cause the compression joint surface of the fluoroplastic to be damaged by creep and friction, so that leakage can be generated, and the service life of the butterfly valve can be shortened.

Problem 4: the inner surface of the flow passage-lining is of a mountain-shaped structure, which can reduce the area of the flow passage and cause the performance reduction of the butterfly valve; the metal material has radial connected butterfly plate bulges, which occupy the flow passage area.

Problem 5: fluid torque and hydrostatic torque- -not described.

Problem 6: high temperature resistance-rubber materials inherently lack good high temperature resistance, while fluoroplastic convex trapezoidal cross-section materials are too large in volume to maintain structural strength at high temperatures and greatly reduce high temperature resistance.

Problem 7: butterfly plate strength-having a diameter link with the butterfly plate protrusion and a tapered cross-section can provide high strength.

Reference scheme five:

japanese patent publication No. JP2003166654A, button fly VALVE, 2003, the reference aims to improve the sealing performance of the BUTTERFLY VALVE at high and normal temperatures, and the required torque is not increased by the high-temperature expansion of the back ring; the reference solution further includes a volume-dispersing groove formed in the inner circumferential surface of the valve body, so that the back ring made of rubber can expand at high temperature to reduce the extrusion of the inner surface of the fluoroplastic lining.

Problem 1: material deformation-when the linear sealing is performed with the fluoroplastic-encapsulated butterfly plate, the problem of creep due to a large amount of material deformation caused by compression sealing is relatively solved, but high pressure resistance cannot be provided.

Problem 2: the contact angle becomes smaller when the butterfly plate packaged by fluoroplastic is used for linear sealing, and the rubber back ring is provided with the convex inclined surface, so that the requirement of the butterfly plate on the interference sliding friction torque of the inner surface of the lining with a smaller area is low, and the narrow metal arc surface can apply smaller tension or shearing force to the packaged fluoroplastic, and the packaging fluoroplastic of the thin butterfly plate can not fail.

Problem 3: axial bore surface-no further description is provided.

Problem 4: the flow channel is provided with a convex inclined plane on the rubber back ring, so that the inner surface of the lining is slightly convex inwards, and the performance of the butterfly valve cannot be reduced; the performance is affected by the large flow passage area occupied by the protruding butterfly plates and the radial connection.

Problem 5: fluid torque and hydrostatic torque- -not described.

Problem 6: high temperature resistance-volume dispersion grooves are also provided on the inner peripheral surface of the valve body to allow the back ring made of rubber to expand at high temperature to reduce extrusion on the inner surface of the liner of the fluoroplastic lining, but the linear seal has reduced sealing performance in high temperature applications.

Reference case six:

JP2012219819A a, advanced patent publication No. h, air seal OF BUTTERFLY VALVE, the reference aims at improving the sealing performance OF the BUTTERFLY VALVE, especially for the middle part OF the inner surface OF the liner is made into a ring-shaped concave spherical surface and connected to the shaft hole surface with the spherical concave surface, the outer edge OF the BUTTERFLY plate can make an effective band-shaped seal OF a whole circle to improve the sealing effect OF the VALVE and reduce the torque requirement, and the comparison analysis proves that the effective sealing can be realized by uniformly generating the compression deformation.

Problem 1: when the material deformation is used for sealing the butterfly plate in a belt shape, the small-area annular concave spherical structure is utilized, the sealing effect that the outer edge of the butterfly plate with a larger area is in compression joint but only a small amount of volume is deformed is generated, the problem of creep of a large amount of material deformation caused by compression joint sealing is relatively avoided, and the butterfly plate has high-pressure tolerance capability.

Problem 2: the thickness of the interference sliding butterfly plate packaged by the fluoroplastic is larger, the contact angle is reduced by utilizing the annular concave spherical surface when the belt-shaped sealing is carried out, in the process of interference sliding friction, materials are only slightly tightened, the torque requirement is low, only small-volume interference friction can be carried out, the thin-layer fluoroplastic of the concave spherical surface bears less tension and less shearing force, and the thin-layer fluoroplastic of the concave spherical surface has longer service life. When the outer edge of the butterfly plate packaged by the fluoroplastic is subjected to interference sliding friction, the metal corner edges inside the butterfly plate apply less tension or shearing force to the packaged fluoroplastic, and the problem of creep of the packaged fluoroplastic is avoided.

Problem 3: axial bore surface-the original spherical surface is maintained, but large area contact still has wear problems.

Problem 4: the middle of the inner surface of the flow channel and the lining is provided with a small annular concave spherical surface, the flow channel area can not be reduced, the performance of a butterfly valve can not be reduced, the butterfly plate is only provided with a butterfly plate bulge at the two shaft ends, the large flow channel area is not occupied, and the performance of the butterfly plate can not be influenced by the thick flat plate of the section of the butterfly plate.

Problem 5: fluid torque and hydrostatic torque- -not described.

Problem 6: high temperature tolerance-there is small annular concave sphere in the middle of the inside lining surface, representing that the material deformation is more easily produced because of thinner thickness in the concave part of the inside lining surface, the inside lining surface can contract inwards relatively easily at high temperature, the high temperature tolerance can be influenced because of the inward contraction of the concave sphere at high temperature, but the high temperature expansion of the back ring rubber can also influence the outward protrusion of the concave sphere and reduce the high temperature tolerance.

Problem 7: butterfly plate strength-with the protruding and platelike cross-section of butterfly plate, the thickness that butterfly plate strength relies on can provide high strength structure in middle and small-size butterfly plate.

Reference scheme seven:

the 2015 chinese patent publication No. CN204344951U, High-precision and abrasion-resistance butterfly valve, the reference aims to improve the inner surface of the lining to be a concave spherical structure, hereinafter referred to as a concave spherical surface, to improve the sealing effect of the valve and reduce the torque requirement, the lining of the valve is made of fluoroplastic, the butterfly plate is also made of fluoroplastic, it is not described whether the metal butterfly plate encapsulated by fluoroplastic can be regarded as a butterfly plate to make linear sealing, and the rubber back ring is installed in the groove of the inner surface of the valve body to increase the sealing performance of the concave spherical surface.

Problem 1: if the fluoroplastic is used for manufacturing the concave spherical structure, and the linear sealing is performed by using the butterfly plate packaged by the fluoroplastic, the problem of creep of a large amount of material deformation is solved in the sealing effect of small-area deformation, and high pressure resistance cannot be provided.

Problem 2: the contact angle is small when the interference sliding butterfly plate is used for linear sealing, the interference sliding with a small area is performed when the butterfly plate is rotated, the friction is small, the torque requirement is low, the thin fluoroplastic layer of the concave spherical surface lacks the fixation of back ring rubber and bears tension and shearing force, and the thin fluoroplastic layer of the concave spherical surface is easy to wrinkle and damage so as to allow corrosive liquid to permeate.

Problem 3: axial bore surface- -maintaining the original spherical surface, no further description is provided.

Problem 4: the area of the flow channel, i.e., the inner surface of the lining, is a concave spherical surface, which reduces the effective area of the flow channel and the performance of the butterfly valve.

Problem 5: fluid torque and hydrostatic torque- -not described.

Problem 6: high temperature resistance-the inner surface of the lining is a concave spherical surface, which represents the length of the inner surface of the lining that the section in the flow passage direction is expanded into a straight line, and the length is longer than the width of the valve body, the concave spherical surface can contract inwards at high temperature, the structure of the concave spherical surface can not be maintained by the back ring, and the back ring rubber expands towards the center of the sphere at high temperature, so that the high temperature resistance can be greatly reduced.

Problem 7: butterfly plate strength-with the convex and tapered cross-section of the butterfly plate, high temperature and high pressure resistance can be provided.

Reference scheme eight:

japanese patent publication No. JP2016041967A, a VALVE BODY OF BUTTERFLY VALVE AND THE BUTTERFLY VALVE, the reference is newly developed from Japanese patent publication No. JP2004239343, VALVE ELEMENT OF BUTTERFLY VALVE, Japanese patent publication No. JP2007032683A, BUTTERFLY VALVE, two prior arts in 2004, the reference is used on metal BUTTERFLY plates, the method can also be applied to a butterfly plate packaged by fluoroplastic, and the purpose of the reference scheme is to improve the weight, flow resistance and torque of the butterfly valve, which is achieved by reducing the weight of the butterfly plate structure without reducing the strength of the butterfly plate, while maintaining high performance in sealing and fluid flow, when the butterfly plate is closed, the butterfly plate is strong enough to withstand line pressure without deforming to cause seal failure, when the butterfly plate is opened, the area of the flow channel cannot be obviously reduced by the butterfly plate positioned in the pipeline flow channel, and the butterfly plate cannot cause fluid to generate turbulence and cavitation erosion to increase flow resistance. The butterfly plate structure of this reference has a diameter in the vertical direction that is linked to the butterfly plate protrusion to provide structural rigidity, and also has ribs with a horizontal elliptical cross-section, and a ring with a thickness that is one time the thickness of the butterfly plate is provided near the outer edge of the butterfly plate to reinforce the structural strength of the butterfly plate side wings.

Problem 1: the deformation of the material, the butterfly plate is linearly sealed, the thickness of the outer diameter side of the metal sheet of the butterfly plate is 2.5mm, the reference does not disclose the condition of the inner surface of the lining, and the width of the compression joint surface is only 2.5mm when the fluoroplastic lining is used, so that the high-temperature and high-pressure resistance cannot be provided.

Problem 2: interference sliding, the reference does not disclose the conditions of the inner surface of the liner, and the substantially linear seal can achieve low deformation and low torque effects, and when used in fluoroplastic packaging of butterfly plates, interference sliding under high packing can cause deformation and creep of the material of the fluoroplastic packaging, so that high temperature and high pressure resistance cannot be provided.

Problem 3: the shaft hole surface and the shaft sealing surface are spherical curved surfaces.

Problem 4: the diameter of the flow channel is connected with the butterfly plate bulge, so that a large flow channel area is occupied, and although the rib plate with the elliptical cross section in the horizontal direction occupies the flow channel area, the turbulence of the flow channel is reduced.

Problem 5: fluid torque and hydrostatic torque, reducing turbulence and reducing cavitation can reduce fluid torque.

Problem 6: high temperature resistance, linear sealing and cannot be improved.

Problem 7: the strength of the butterfly plate is that the diameter of the butterfly plate is connected with the bulge of the butterfly plate, the thickness of the plate-shaped section is only 2.5mm, the side wing of the butterfly plate is also provided with a rib plate with an elliptical section in the horizontal direction, and an annular structure with the thickness being one time of the thickness of the butterfly plate is arranged near the outer edge of the butterfly plate, so that enough strength can be provided.

Reference table nine:

the patent publication No. CN106415087A of Chinese patent in 2017, Seal Structure for Butterfly Valve, the reference aims at improving the Butterfly Valve to have good sealing performance at high temperature and normal temperature, and the required torque is not increased due to the high-temperature expansion of the back ring; a seal structure of a butterfly valve, wherein liners made of resin material are respectively provided on inner peripheral surfaces of a valve body surface, the liners are provided with shaft holes at diametrically opposite positions, including the shaft holes and the shaft hole surfaces, a butterfly plate has a butterfly plate protrusion capable of passing through the liners and a rubber back ring and being mounted in a shaft hole portion of a valve body, and a valve shaft is mounted in the center hole of the butterfly plate protrusion, and an outer edge of the butterfly plate is press-sealed on the inner surface of the liner when the valve shaft is rotated, characterized in that an inner diameter of the valve body liner is set as follows: the inner diameter of the inner surface of the liner is deformed to an inner diameter smaller than the outer diameter of the butterfly plate by the elastic force of the rubber back ring when the valve is opened, and the inner diameter before the deformation is returned to the inner diameter before the deformation by the elastic force of the rubber back ring by pressing the butterfly plate when the valve is closed, and the inner diameter before the deformation is set to include a tolerance equal to or slightly larger than the outer diameter of the butterfly plate.

Problem 1: the thickness of the material deformation amount on the outer diameter side of the metal sheet of the butterfly plate is 3mm, the butterfly plate packaged by the fluoroplastic is used for linear sealing, the inner diameter of the inner surface of the lining after compression is close to the original diameter which is not compressed by the rubber back ring and is also very close to the outer diameter of the butterfly plate, namely the inner surface of the lining is not compressed by the outer edge of the butterfly plate to generate stretching, the disclosed compression ratio is about 13% and 1.3mm/10mm, the purpose of the material deformation creep problem caused by compression sealing is reduced, the torque of about 23% can be reduced by pursuing linear sealing and low packing amount of about 13%, but the width of a compression surface is only 3mm and high-pressure and high-temperature resistance cannot be provided.

Problem 2: interference sliding is carried out, the outer edge of the butterfly plate is only contacted with the annular sealing surface which is raised in the middle of the inner surface of the lining to carry out linear sealing, the contact angle is smaller, the torque requirement is low, interference sliding friction with a smaller area is carried out on the inner surface of the lining by the outer edge of the butterfly plate, the tightening amount is about 13%, smaller tension or shearing force is applied to the inner surface of the lining, and 23% torque reduction can be achieved; the outer circular arc of the butterfly plate inner metal with the thickness of 3mm can apply smaller tension or shear force to the encapsulated fluoroplastic, and as in the prior art, the butterfly plate metal sheet is provided with the through hole close to the outer diameter side, so that the strength of the encapsulated fluoroplastic can be increased, and the encapsulation failure of the butterfly plate can not be caused.

Problem 3: the shaft hole surface is provided with bosses on the back sides of two ends of the shaft hole to enhance the sealing performance of the shaft hole surface and is connected to the inner surface of the lining.

Problem 4: the flow channel, the bellied annular seal face in the middle of the inside lining internal surface can cause the runner area to reduce about 5%, only the butterfly plate arch does not occupy big runner area at two axle ends, and the butterfly plate cross-section can not influence the performance for the toper.

Problem 5: fluid torque and hydrostatic torque, not described.

Problem 6: high temperature resistance, the rubber back ring supports the middle convex sealing surface on the inner surface of the inner liner, so that the rubber back ring can expand to the space between the inner liner and the valve body at high temperature, excessive extrusion on the tubular part of the fluoroplastic inner liner is reduced, and the high temperature resistance cannot be improved due to the limitation of linear sealing.

Problem 7: butterfly plate intensity, it is protruding and the toper cross-section can provide resistant high structural strength to have the butterfly plate.

Reference case ten:

chinese patent publication No. CN100376828C, Valve body of mitter Valve, 2008, aims to reduce the fluid resistance at full opening and intermediate opening without reducing the flow coefficient Cv value at the time of full opening, and to make the Valve body lighter in weight.

Reference case eleven:

the butterfly valve model of Tomoe Valves, Inc. of Japan, No. Tomoe Valves USA catalog-846t-847t-847q-20150601, is a product model of this company that provides a table of the Cv values of the flow coefficient of the fluoroplastic butterfly valve, which are referenced for comparison with a 3 inch diameter butterfly valve.

After the above reference schemes are discussed in the problems 1 to 7, it is found that for the high temperature application of ≦ 200 ℃, the two problems of the sealing width and the material deformation caused by the interference sliding are not completely solved and cannot meet the requirement of high temperature and high pressure resistance, and the performance problems of low torque, high flow rate, high Cv value, long service life, high reliability and the like also need to be clarified, so that various existing solutions of the existing fluoroplastic lining butterfly valve cannot meet the specification of the special-purpose butterfly valve below the present invention.

Corrosive liquid: conveying hydrofluoric acid, hydrochloric acid, sulfuric acid and other fluids, wherein the thickness of the material contains corrosion margin.

Performance quality: high flow, low torque, long service life, high temperature and pressure resistance and high reliability.

Maximum temperature: special use ≦ 200 ℃.

The highest pressure: special use ≦ 3kg @200 ℃.

Disclosure of Invention

The invention provides an innovative invention which aims to meet the requirements and adopts a composite sealing mode for a butterfly plate and a valve body to solve the problem of the sealing width of the butterfly plate and the valve body under high-temperature operation and reduce the defect of interference sliding, and has the advantage of maintaining high performance, so that the butterfly valve structure can be improved in the aspects of sealing pressure resistance, torque reduction, high-temperature tolerance and valve performance.

In order to achieve the purpose, the invention adopts the technical scheme that:

a fluoroplastic butterfly valve structure, comprising: a valve body, a butterfly plate, a liner and a back ring;

the valve body is annular and comprises an upper valve body and a lower valve body which are horizontally divided into semicircular arcs, the upper valve body and the lower valve body are tightly locked into a whole, the assembling direction of the upper valve body and the lower valve body is axial, the valve body is provided with an inner circumferential surface, and the inner circumferential surface is provided with a groove with a trapezoidal section;

the butterfly plate is disc-shaped and comprises a butterfly plate outer edge, two axial ends of the butterfly plate outer edge are respectively provided with a horizontal sealing end face, the horizontal sealing end faces are connected with a ring curved surface of the butterfly plate outer edge, and the connecting positions are respectively provided with a tangent angle of an arc; the horizontal sealing end faces at the two axial ends of the outer edge of the butterfly plate are respectively provided with a valve shaft and a bulge, the valve shaft and the bulge are concentric, the bulge is provided with a shaft sealing face and a raised sealing ring, and the shaft sealing face, the corner cut and the ring curved face are connected to form a butterfly plate sealing face;

the lining is annular relative to the valve body and is provided with an inner diameter side and an outer diameter side, two ends of the lining respectively comprise a radial flange, the lining comprises a tubular part, and the inner diameter side of the tubular part is the inner surface of the lining; the inner lining is respectively provided with a horizontal sealing plane at the two axial ends, the thickness of the horizontal sealing plane is greater than that of the tubular part, and the thickness covers the inner diameter side and the outer diameter side of the inner lining; a shaft hole and a shaft hole surface are arranged on the horizontal sealing plane, the shaft hole surface is respectively arranged on the inner diameter side and the outer diameter side which surround the periphery of the shaft hole, a connecting angle of an arc is arranged at the connecting position of the inner diameter side of the horizontal sealing plane and the inner diameter side of the tubular part, and a sealing groove is arranged on the shaft hole surface on the inner diameter side; the shaft hole surface and the connecting angle on the inner diameter side are connected with the inner surface of the lining to form a lining sealing surface; the inner lining is arranged on the inner circumferential surface of the valve body;

the back ring is an elastic body with a trapezoidal section, is arranged in the groove and is tightly attached to the outer diameter side of the tubular part;

in the butterfly plate sealing surface and the lining sealing surface, the shaft hole surface is opposite to the shaft sealing surface, the butterfly plate outer edge ring curved surface is opposite to the lining inner surface, the sealing ring is opposite to the sealing groove, and the connecting angle is opposite to the corner cut, and the parts are tightly closed to form a continuous and smooth sealing surface; when the butterfly plate is turned from full opening to closing, the outer edge of the butterfly plate is firstly contacted with the inner surface of the lining at a position close to the valve shaft, the outer edge of the butterfly plate is sequentially contacted with the inner surface of the lining from a position close to the valve shaft to a central position of the butterfly plate, a connecting line connecting a contact point of the outer edge of the butterfly plate and the inner surface of the lining and a rotating shaft center of the valve shaft forms a contact angle with the central line, and any contact point of the outer edge of the butterfly plate and the inner surface of the lining has different contact angles; when the outer edge of the butterfly plate slides in an interference manner with the inner surface of the lining, the outer edge of the butterfly plate and a contact surface of the lining with deformation form a sliding surface, and a tangent of the sliding surface and a tangent of the inner surface of the lining perpendicular to the valve shaft form a sliding included angle; the annular curved surface comprises a composite seal formed by a cylindrical surface with unequal width and a curved surface with unequal width; the sealing width of the unequal-width cylindrical surface has a narrower sealing width at a position close to the valve shaft and has the widest sealing width at a position close to the center of the butterfly plate; the sealing width of the unequal-width cylindrical surface at the position close to the valve shaft exceeds more than 50% of the thickness of the outer edge of a metal butterfly plate in the butterfly plate, and the sealing width of the unequal-width cylindrical surface at the position close to the center of the butterfly plate exceeds more than 70% of the thickness of the outer edge of the metal butterfly plate; the unequal-width curved surface extends from the surface of the butterfly plate to the outer edge of the butterfly plate; the unequal-width curved surface has the longest smooth arc line at the position close to the valve shaft and the shortest smooth arc line at the position close to the center of the butterfly plate, and is configured in the closing rotating direction of the butterfly plate; when the butterfly plate is closed or opened, the unequal-width curved surface and the inner surface of the lining slide in an interference manner.

The fluoroplastic butterfly valve structure comprises the metal butterfly plate and a fluoroplastic package, wherein the metal butterfly plate is wrapped by the fluoroplastic package, the annular curved surface is located on the fluoroplastic package, a corresponding curved surface structure is also arranged on the outer edge of the metal butterfly plate, and the metal butterfly plate comprises a non-uniform-width cylindrical surface and a non-uniform-width curved surface, the non-uniform-width curved surface is provided with the longest smooth arc line close to the valve shaft, the shortest smooth arc line close to the central part of the butterfly plate, and the non-uniform-width curved surface is arranged in the closing rotation direction of the butterfly plate.

The fluoroplastic butterfly valve structure is characterized in that the thickness of the butterfly plate of the 3-inch butterfly valve is 8mm, the sealing width of the outer edge of the butterfly plate is more than 4mm at the position close to the valve shaft, and the sealing width of the outer edge of the butterfly plate is more than 5.6mm at the position close to the center of the butterfly plate.

The fluoroplastic butterfly valve is constructed in such a manner that the compression ratio of the sealing surface is equal to the ratio of the packing amount to the thickness of the back ring, and the compression ratio ranges from 15% to 20%.

The fluoroplastic butterfly valve structure is characterized in that the butterfly plate is divided into two butterfly plate side wings by the protruding parts at two ends, and the cross section of each butterfly plate side wing is a plate-shaped cross section or a conical cross section.

The fluoroplastic butterfly valve structure is characterized in that a convex ring is arranged at the bottom of the groove, the height of the convex ring is smaller than the depth of the groove, when the back ring is installed in the groove, an expansion space is formed, and the width of the convex ring is equal to 1.5-2 times of the thickness of a metal butterfly plate inside the butterfly plate and is smaller than the width of the bottom of the groove.

The fluoroplastic butterfly valve structure, wherein the inner diameter of the back ring is substantially equal to the inner diameter of the valve body; the outer diameter of the tubular portion is substantially equal to the inner diameter of the valve body.

The fluoroplastic butterfly valve is constructed in a way that smooth arcs of the curved surfaces with different widths are approximate to elliptic curves.

the valve body is annular and comprises an upper valve body and a lower valve body which are horizontally divided into semicircular arcs, wherein the upper valve body and the lower valve body are both provided with a locking part and a shaft hole part;

the butterfly plate is disc-shaped and comprises a butterfly plate outer edge, two axial ends of the butterfly plate outer edge are respectively provided with a horizontal sealing end face, the horizontal sealing end faces are connected with a ring curved surface of the butterfly plate outer edge, and the connecting positions are respectively provided with a circular arc-shaped tangent angle; the horizontal sealing end surfaces at two axial ends are respectively provided with a bulge and a valve shaft, the bulge and the valve shaft are concentric, the bulge is provided with a shaft sealing surface and a raised sealing ring, and the shaft sealing surface, the cut corner and the ring curved surface are connected to form a butterfly plate sealing surface;

the lining is annular relative to the valve body and is provided with an inner diameter side and an outer diameter side, two ends of the lining respectively comprise a radial flange, the lining comprises a tubular part, and the inner diameter side of the tubular part is the inner surface of the lining; the inner lining is respectively provided with a horizontal sealing plane at two axial ends, the thickness of the horizontal sealing plane is greater than that of the tubular part, and the thickness covers the inner diameter side and the outer diameter side of the inner lining; the horizontal sealing plane is provided with a shaft hole and a shaft hole surface, the shaft hole surface is respectively arranged on the inner diameter side and the outer diameter side which surround the periphery of the shaft hole, the joint of the inner diameter side of the horizontal sealing plane and the inner diameter side of the tubular part is respectively provided with a connecting angle of an arc, and the shaft hole surface on the inner diameter side is provided with a sealing groove; the shaft hole surface and the connecting angle on the inner diameter side are connected with the inner surface of the lining to form a lining sealing surface; the inner lining is arranged on the inner circumferential surface of the valve body;

the back ring is an elastic body with a trapezoidal section, is arranged in the groove with the trapezoidal section and is tightly attached to the outer diameter side of the tubular part;

in the butterfly plate sealing surface and the lining sealing surface, the shaft hole surface is opposite to the shaft sealing surface, the butterfly plate outer edge ring curved surface is opposite to the lining inner surface, the sealing ring is opposite to the sealing groove, and the connecting angle is opposite to the corner cut, and the parts are tightly closed to form a continuous and smooth sealing surface;

and a reinforcing part is respectively arranged on the outer diameter side of the horizontal sealing plane and two sides of the shaft hole along the tubular part, the width of the reinforcing part is more than twice of the thickness of a metal butterfly plate in the butterfly plate, and the thicknesses of the horizontal sealing plane and the tubular part can be smoothly changed.

The fluoroplastic butterfly valve structure is characterized in that the reinforcing part smoothes the thickness of the connecting angle.

A fluoroplastic butterfly valve structure, comprising:

a valve body;

a butterfly plate pivoted on the valve body by a valve shaft, wherein the butterfly plate is used for opening or closing the valve body by means of the pivoting of the valve shaft;

the butterfly plate is provided with a butterfly plate outer edge, and the butterfly plate outer edge is provided with a ring curved surface which comprises a cylindrical surface with unequal widths; the sealing width of the cylinder surface with unequal width is gradually widened from the valve shaft to the central part of the butterfly plate, the sealing width of the cylinder surface with unequal width close to the valve shaft exceeds more than 50% of the thickness of the outer edge of a metal butterfly plate inside, and the sealing width of the cylinder surface with unequal width close to the central part of the butterfly plate exceeds more than 70% of the thickness of the outer edge of the metal butterfly plate.

The fluoroplastic butterfly valve structure is characterized in that the annular curved surface further comprises a curved surface with unequal width and a cylindrical surface with unequal width to form a composite sealing structure; the unequal-width curved surface extends from the surface of the butterfly plate to the outer edge of the butterfly plate; the smooth arc line of the unequal-width curved surface is in a gradually narrowed shape from the valve shaft to the central part of the butterfly plate, and the unequal-width curved surface is configured in the closing rotation direction of the butterfly plate.

The efficacy of the invention is illustrated below:

problem 1: the material deformation amount, namely the unequal-width cylindrical surface of the composite seal, can pursue larger sealing width and reasonable crimping pressure to achieve sealing, can adopt more proper compression ratio to achieve sealing requirements, the material on the inner surface of the lining has less deformation and is less prone to creep, the larger sealing width represents high pressure resistance, and the larger pressure change can be borne; and the material still has large tracts of land support when high temperature, and high temperature tolerance improves, and these advantages all can improve butterfly valve life-span.

Problem 2: the interference sliding-composite sealing unequal-width curved surface replaces the existing angle side, the contact angle provided by the unequal-width curved surface is reduced, the sliding length is shortened, the interference sliding of relatively smooth sliding is carried out, the tensile tension and the shearing force born by the material on the inner surface of the lining are reduced, the material creep is not easy to occur, the friction is also reduced, the torque requirement is reduced, the pressure resistance and the high-temperature tolerance of the butterfly valve are improved, and the service life of the butterfly valve is prolonged.

Problem 3: the shaft sealing surface of the shaft hole surface-the horizontal sealing end surface is provided with a raised sealing ring which can perform interference compression sealing with the sealing groove of the shaft hole surface of the horizontal sealing plane to reduce the compression sealing area, reduce the raised outer diameter of the butterfly plate and increase the flow passage area, and also reduce the abrasion and creep caused by sliding friction, reduce the leakage risk and prolong the service life of the butterfly valve; the two sides of the shaft hole are respectively provided with a reinforcing part, so that the thickness of the horizontal sealing plane and the thickness of the tubular part can be smoothly changed, and the sealing capability of the horizontal sealing plane is improved.

Problem 4: when the butterfly plate is opened to form a slit flow passage, the unequal-width curved surface can increase the width of the slit flow passage, and the outer edge of the butterfly plate is a smooth curved surface, so that the flow of the butterfly plate in small-angle opening can be improved; the butterfly plate is not connected in diameter and cannot occupy large flow passage area, the section of the side wing of the butterfly plate adopts a plate-shaped section or a conical section, the separated small outer diameter protruding parts on two sides of the valve shaft of the butterfly plate occupy small flow passage area, and the inner diameter surface of the lining is cylindrical and equal to the inner diameter of the pipeline, so that enough flow passage area and flow can be ensured.

Problem 5: the fluid torque and the static pressure torque-the butterfly plate side wings and the inner surface of the lining form a slit flow passage, the unequal-width curves can increase the width of the slit flow passage to have larger flow, and reduce separated flow and turbulent flow to ensure that the fluid torque is lower; at the position close to the valve shaft, the minimum sealing width of the unequal-width cylindrical surface exceeds more than 50% of the thickness of the outer edge of the metal butterfly plate in the butterfly plate; the minimum sealing width of the unequal-width cylindrical surface close to the central part of the butterfly plate exceeds more than 70% of the thickness of the outer edge of the metal butterfly plate in the butterfly plate, so that the static pressure torque resistance can be greatly improved, and the risk of static pressure leakage is reduced.

Problem 6: high temperature tolerance, namely the unequal-width cylindrical surface has wider sealing width, and the unequal-width curved surface has smooth interference sliding, so that the material deformation of the inner surface of the lining can be reduced, and the high temperature and high pressure tolerance is good; the tubular part of the lining has no complex structure, and the high-temperature deformation is greatly reduced; the trapezoidal groove on the inner side of the valve body can accommodate high-temperature expansion of the back ring.

Problem 7: butterfly plate strength-the boss of the butterfly plate is separated and not connected diametrically, and the thick plate-like section or the tapered section adopted by the section of the side wing of the butterfly plate can provide high strength.

Drawings

Fig. 1 is the appearance and assembly of the fluoroplastic butterfly valve of the present invention.

FIG. 2A is a cross-sectional view of a liner including a reinforcement.

FIG. 2B is a sealing plan view of a liner including a reinforcement.

Fig. 3 is a view of the liner and back ring assembly.

Fig. 4A is an axial top view of the butterfly plate of the invention.

FIG. 4B is a side view of the butterfly plate of the present invention.

Fig. 4C is a perspective view of the unequal-width cylindrical surface and the unequal-width curved surface of the butterfly plate of the present invention.

Fig. 4D is a perspective view of a metal butterfly plate of the present invention.

Fig. 5Ai, 5Aii, and 5Aiii are schematic views of the contact points of the butterfly plate of the present invention with the inner surface of the liner at cross-sectional positions a-a, b-b, and c-c, respectively.

FIG. 5B is a schematic view of the butterfly plate of the present invention contacting the liner to cause the liner and back ring to be crushed and deformed to form a seal.

Fig. 5C is an upper view of the butterfly plate of the invention in the axial direction.

FIG. 5D is a cross-sectional view of the contact point of the butterfly plate of the invention with the inner surface of the liner at section a-a.

FIG. 5E is an interference sliding cross-sectional view of the butterfly plate of the invention.

FIG. 6A is a schematic view of a slit flow passage of the butterfly valve of the present invention.

FIG. 6Bi is a graph showing the flow coefficient Cv of the butterfly valve of the present invention at different opening angles.

Fig. 6Bii is a graph of the flow coefficient Cv for the ten reference case 3 inch butterfly valve at various opening angles.

Fig. 6Biii is a graph of the flow coefficient Cv for the 3 inch butterfly valve of reference case eleven at various opening angles.

Fig. 7A is an external view of a conventional fluoroplastic butterfly valve.

Fig. 7B is a structural view of a conventional fluoroplastic packaging butterfly plate.

Fig. 7C is a view of the combination of the inner liner and the back ring of a conventional fluoroplastic butterfly valve.

Fig. 7D is a cross-sectional view of a tubular portion of a prior art inner liner of a fluoroplastic butterfly valve.

Fig. 7E is a schematic diagram of the torque required by the prior art butterfly plate when closing the butterfly valve.

FIG. 7F is a schematic diagram of the torque required to open the butterfly valve to form a slit flow passage.

Fig. 8Ai, 8Aii and 8Aiii are schematic views of the contact points of the band-shaped sealing butterfly plate of the prior fluoroplastic butterfly valve with the inner surface of the liner at the section positions a-a, b-b and c-c, respectively.

Fig. 8B is a graph of the deformation of the sealing surface and the crimping pressure of the band seal of the prior art fluoroplastic butterfly valve.

Fig. 8C is a shape diagram of the sealing surface of the strip seal of the prior art fluoroplastic butterfly valve.

Fig. 8D is a cross-sectional view of the prior art fluoroplastic butterfly valve with the strip seal at the contact point with the inner surface of the liner at section a-a.

Fig. 8E is an interference sliding cross-sectional view of a prior art fluoroplastic butterfly valve with a band seal.

Fig. 9Ai, 9Aii, and 9Aiii are schematic views of the contact points of the prior art linear sealing butterfly plate with the inner surface of the liner at cross-sectional positions a-a, b-b, and c-c, respectively.

Fig. 9B is a graph of the sealing surface deformation and the crimping pressure of a linear seal of a conventional fluoroplastic butterfly valve.

Fig. 9C is a shape diagram of a sealing surface of a linear seal of a conventional fluoroplastic butterfly valve.

Fig. 9D is a cross-sectional view of the linear seal of a prior art fluoroplastic butterfly valve at the contact point with the inner surface of the liner at section a-a.

Fig. 9E is an interference sliding cross-sectional view of a linear seal of a prior art fluoroplastic butterfly valve.

Description of reference numerals: 1-a symmetrical butterfly valve; 2-a valve body; 21-an upper valve body; 211-a locking portion; 212-a shaft bore portion; 22-a lower valve body; 221-a locking portion; 222-a shaft hole portion; 23-inner circumferential surface; 232-a trench; 233(γ) -ladder angle; 234-convex ring; 235-an expansion space; 236(t2) -torus width; 237(s1) -trench depth; 238(t3) — bottom width; 239(s2) -torus height; 24-locking the screw hole; 25-center line; 3-lining; 31-a tubular portion; 311-inner liner surface; 312-shaft hole; 315-tubular section outside diameter; 318-reinforcement; 32-a radial flange; 4- -dorsal loop; 41-inner diameter of dorsal ring; 42-trapezoidal cross section; 43(α) -trapezoidal included angle; 45(s3) -thickness; 46-a shaft hole portion; 5-a butterfly plate; 51-metal butterfly plates; 511-outer edge; 513-a coupling hole; 514-unequal width cylinder surface; 515-unequal width curved surface-; 515 a-longest arc; 515 c-shortest arc; 516-butterfly plate flank-; 517-boss-; 518-horizontal seal end face-; 519-cutting corners-; 53-outer edge of butterfly plate; 531-toroidal curved surface; 532-unequal width cylinder surface; 533-unequal width curved surface; 533 a-longest smooth arc; 533 b-short smooth arc; 533 c-shortest smooth arc; 54-a boss; 544-an axial hole; 55-a valve shaft; 55 a-upper valve shaft; 55 b-lower valve shaft; 56-butterfly plate side wing; 57-outer diameter of butterfly plate; 6-sealing surface; 61-linear sealing; 62-band sealing; 63(B) -seal width; 631(t1) -metal butterfly plate thickness-; 632-sealing plane-; 633-corner joint-; 634-shaft bore face; 634 a-sealing groove; 635-sealing the end face; 636-cutting corners; 637-shaft sealing face; 637 a-sealing ring; 64(p) -crimp pressure; 65(ε) -packing amount; 66-inward bulge; 66 a-convex curve; 66b (h) -bump height; 67-composite seal; 68(δ) -inner liner deformation-; 69-packaging; 69 a-package deformation-; 7-interference sliding; 71(θ) -contact angle; 72-contact point; 73(R) -arm of rotation; 74(ψ) -slip angle; 75(F) -friction; 79(T) -torque; 791-direction of rotation; 792(Th) -fluid torque; 793(Tp) -hydrostatic torque; 794(Tf) -friction torque; 8-a flow channel; 81-slit flow channel; 811-flow line; 812-a reflux zone; 813(W) -slit width; 814-sudden expansion flow channel; 815-a tapered flow channel; 82(Ps) -static pressure; 9-fluoroplastic butterfly valve; 91-a valve body; 911-inner circumferential surface-; 912-groove-; 913-an upper shaft hole portion; 914-lower shaft hole part; 92-a butterfly plate; 92 a-a linear sealing butterfly plate; 92 b-band sealing butterfly plate; 92 c-metal butterfly plate; 921-butterfly plate side wings; 922-outer edge of butterfly plate-; 923-a toroidal curved surface; 923 a-corner; 924-conic surface-; 927-butterfly plate bulge-; 928-shaft hole-; 929-diameter link-; 93-inner lining-; 931-the tubular portion; 932-radial flange-; 933-lining inner surface-; 937-axial hole-; 94-dorsal loop-; 941(t4) -thickness; 95-valve shaft.

Detailed Description

Referring to fig. 1, fig. 2A, fig. 2B, fig. 3, fig. 4A, fig. 4B, fig. 4C and fig. 4D, a fluoroplastic symmetric butterfly valve 1 includes a valve body 2, an inner liner 3, a back ring 4 and a butterfly plate 5.

The valve body 2 is circular, and comprises two parts horizontally divided into a semicircular arc, namely an upper valve body 21 and a lower valve body 22 which are tightly locked into a whole by two bolts, the assembling direction of the upper valve body 21 and the lower valve body 22 is an axial direction, the upper valve body 21 is provided with a tight lock part 211 and a shaft hole part 212, and the lower valve body 22 is provided with a tight lock part 221 and a shaft hole part 222; an inner circumferential surface 23 of the valve body 2 is used for mounting the fluoroplastic lining 3; a groove 232 with a trapezoidal and included angle 233(γ) is formed on the inner circumferential surface 23 for installing the back ring 4 with a trapezoidal cross section 42 and an included angle 43(α), as shown in fig. 3; the bottom of the groove 232 is provided with a protruding ring 234, the height 239(s2) of the protruding ring 234 is less than the depth 237(s1) of the groove 232, and the width 236(t2) of the protruding ring 234 is equal to 1.5 times to 2 times the thickness 631(t1) of a metal butterfly plate 51 inside the butterfly plate 5, please refer to fig. 4A, but less than the bottom width 238(t 3).

The liner 3 is annular relative to the valve body 2, the liner 3 has an inner diameter side and an outer diameter side, two ends of the liner 3 are respectively provided with a radial flange 32, the liner comprises a tubular part 31, the outer diameter 315 of the tubular part 31 is arranged on the inner circumferential surface 23 of the valve body 2, the outer edge 53 of the butterfly plate 5 is pressed on the inner surface 311 of the liner with the tubular part 31 in a cylindrical shape when the liner is closed and is supported by the valve body 2 and the back ring 4 to seal the flow of fluid and bear the pressure and temperature of the fluid, the liner 3 is respectively provided with a horizontal sealing plane 632 at two axial ends, the thickness of the horizontal sealing plane 632 is larger than that of the tubular part 31, the horizontal sealing plane 632 is in a plane structure at the inner diameter side and the outer diameter side, so that the diameter distance between the two horizontal sealing planes 632 is smaller than the inner diameter of the tubular part 31, the liner 3 is connected with the liner 3 at the inner diameter side of the tubular part 31 at the inner diameter side of the horizontal sealing plane 632, the joints are respectively provided with an arc-shaped connecting angle 633; a shaft hole 312 is formed on the horizontal sealing plane 632, a shaft hole surface 634 is respectively formed on the inner diameter side and the outer diameter side of the horizontal sealing plane 632, and is used for press-connection sealing around the periphery of the shaft hole 312, a sealing groove 634a is formed on the shaft hole surface 634 on the inner diameter side, and the shaft hole surface 634 on the inner diameter side and the connecting angle 633 are connected with the inner lining surface 311 to form a complete sealing surface 6; on the outer diameter side of the horizontal sealing plane 632 and on both sides of the shaft hole 312, a reinforcing portion 318 is disposed, which is distributed on a center line 25 and has a width greater than twice the thickness 631(t1) of the metal butterfly plate 51 inside the butterfly plate 5, so that the thicknesses of the horizontal sealing plane 632 and the tubular portion 31 can be smoothly changed to improve the leakage problem of the corner 633, wherein the center line 25 is a line perpendicular to the axial direction and passing through the center of the shaft hole 312.

Referring to fig. 3, the back ring 4 is made of an elastic body made of rubber, and is installed between the groove 232 of the inner circumferential surface 23 of the valve body 2 and the tubular portion 31 of the fluoroplastic lining 3, and is also provided with a shaft hole portion 46 according to the requirement of a valve shaft 55 of the butterfly plate 5, and the inner diameter 41 of the back ring 4 is substantially equal to the inner diameter of the valve body 2; when the back ring 4 is installed inside the groove 232, an expansion space 235 is left to satisfy the thermal expansion requirement at high temperature; the back ring 4 will fill more than 80% of the expansion space 235 when forced tight, almost completely under high temperature expansion; the outer diameter 315 of the tubular portion 31 is substantially equal to the inner diameter of the valve body 2, the inner diameter 41 of the back ring and the inner liner surface 311 being slightly undersized and bulging inwardly due to shrinkage during manufacture; the thickness 45(s3) of the back ring plus the height 239(s2) of the protruding ring 234 is equal to the depth 237(s1) of the groove 232, but the thickness 45(s3) of the back ring 4 may be slightly larger due to shrinkage deformation in the manufacturing process, so that the inner diameter of the back ring 4 is slightly smaller than that of the valve body 2, and the liner inner surface 311 is also inwardly protruded due to the same shrinkage reason in manufacturing, so that the cross section of the liner inner surface 311 becomes a protruded curve 66 a; these all require process control to bring the protrusion height 66b (h) within a reasonable range, since the butterfly plate 5 must produce a sufficient amount of tightening 65 (epsilon) to achieve the sealing effect when mounted to the tubular portion 31 of the liner 3, and these protrusion heights 66b (h) must be regulated during the manufacturing process and also included in the calculation of the amount of tightening 65 (epsilon), see fig. 5Ai, 5Aii, 5 Aiii.

Referring to fig. 4A, 4B, 4C and 4D, the butterfly plate 5 is disc-shaped, the butterfly plate 5 has a butterfly plate outer edge 53, the butterfly plate outer edge 53 has a ring curved surface 531, the butterfly plate 5 has a horizontal sealing end surface 635 at each of the two axial ends, the horizontal sealing end surface 635 is opposite to the horizontal sealing plane 632 of the liner 3, and the connecting position between the horizontal sealing end surface 635 and the ring curved surface 531 has a cut corner 636 with an arc shape, and the cut corner 636 is sealed with a connecting corner 633 at the inner diameter side of the liner 3; the horizontal sealing end face 635 and the horizontal sealing plane 632 are axially and vertically pressed and sealed, the vertical sealing at the cutting corner 636 and the connecting corner 633 is changed into radial sealing, and the smooth thickness of the reinforcing part 318 enables the pressing to be uniform, so that the problem of fluid leakage from the position of the valve shaft 55 is avoided; the horizontal sealing end face 635 is provided with a boss 54 concentric with a valve shaft 55 and the valve shaft 55, the valve shaft 55 has a long upper valve shaft 55a and a short lower valve shaft 55 b; the valve shaft 55 is mounted in the shaft hole portion 212 of the upper valve body 21 and the shaft hole portion 222 of the lower valve body 22 of the valve body 2 through the two shaft holes 312 of the liner 3 so that the butterfly plate 5 can be rotated to adjust the flow rate or open/close the valve; the butterfly plate 5 is divided into two butterfly plate flanks 56 by the protruding portion 54, and the cross section of the butterfly plate flanks 56 may be a plate-shaped cross section or a tapered cross section, wherein a large-sized butterfly valve has a tapered cross section (as shown in fig. 7E), and a small-sized butterfly valve has a plate-shaped cross section (as shown in fig. 4A).

The outer diameter of the outer edge 53 of the butterfly plate 5 is slightly larger than the inner diameter of the inner surface 311 of the liner, and half of the difference is the tightening amount 65 (epsilon) with a single-side radius, as shown in fig. 5Ai, 5Aii, and 5Aiii, the compression ratio of the sealing surface 6 is equal to the ratio of the tightening amount 65 (epsilon) to the thickness 45(s3) of the back ring 4, and the compression ratio ranges from 15% to 22% depending on the material of the back ring 4 and the pressure and temperature resistant requirements, and the thickness 631(t1) of the metal butterfly plate 51 at the outer edge of the butterfly plate side wing 56 can provide a composite seal with a sealing width ≧ 4mm, taking a 3-inch butterfly valve as an example, as shown in fig. 4A.

Referring to fig. 1, a shaft sealing surface 637 of the protruding portion 54 of the horizontal sealing end face 635 is provided with a protruding sealing ring 637a capable of sealing with the sealing groove 634a of the shaft hole face 634 and reducing the outer diameter of the protruding portion 54, so that the pressure-welding seal between the butterfly plate outer edge 53 and the liner inner surface 311 is also connected to the shaft sealing surface 637 and the shaft hole face 634, forming a continuous and reliable sealing surface 6 including the sealing between the horizontal sealing end face 635 and the horizontal sealing plane 632.

Referring to fig. 4A, 4B, 4C and 4D, it is illustrated that the butterfly plate outer edge 53 has a composite sealing structure 67 satisfying high temperature, high pressure, low torque and good service life, and the composite sealing structure 67 includes: the annular curved surface 531 of the outer edge 53 of the butterfly plate is a smooth curved surface formed by a cylindrical surface 532 with unequal width and a curved surface 533 with unequal width, and the curved surface 533 with unequal width is located in the rotating direction 791 of the butterfly plate 5 (see fig. 5D); the positions of the section a-a, the section b-b and the section c-c mentioned herein are the same as the position of the section line of the conventional butterfly valve shown in fig. 7A; the sealing width 63(B) of the unequal-width cylindrical surface 532 has a narrower sealing width 63(B) at the section a-a, a second largest sealing width 63(B) at the section B-B, and a widest sealing width 63(B) at the section c-c, i.e., gradually wider from the position near the valve shaft 55 toward the center of the butterfly plate 5, and the unequal-width cylindrical surface 532 forms a part of the sealing surface 6, the unequal-width cylindrical surface 532 is a corner 535 with respect to the other side of the unequal-width curved surface 533, has a small circular arc radius, is connected to the surface of the butterfly plate side wing 56, and the corner 535 is located on the opening direction side of the butterfly plate 5, and the corner 535 and the inner liner surface 311 generate little interference sliding 7; the unequal-width curve 533 is formed by extending the surface of the wing 56 of the butterfly plate 5 toward the outer edge 53, and the unequal-width curve 533 has a longest smooth arc 533a at the section a-a, a shorter smooth arc 533b at the section b-b, and a shortest smooth arc 533c at the section c-c, i.e. the curve gradually narrows from the position near the valve shaft 55 to the position near the center of the butterfly plate 5; the unequal-width curve 533 will generate the interference sliding 7 with the inner surface 311 of the liner, the longest smooth curve 533a, the shorter smooth curve 533b, and the shortest smooth curve 533c are all approximate elliptical curves, the short diameter of the ellipse is perpendicular to the surface of the butterfly wing 56, and these curves can also be formed by several circular arcs; the outer edge 511 of the metal butterfly plate 51 inside the butterfly plate 5 also has corresponding curved surface structures, such as a butterfly plate side wing 516, a protruding portion 517, a horizontal sealing end surface 518, and a cut corner 519, as shown in fig. 4D, a non-uniform width cylindrical surface 514 and a non-uniform width curved surface 515 have the longest arc 515a at the section a-a position, and have the shortest arc 515c at the section c-c position.

As shown in fig. 4A, the composite sealing structure 67 can satisfy the patent features of high temperature and high pressure: taking a 3-inch diameter butterfly valve as an example, the thickness of the outer edge of the metal butterfly plate 51 is 8mm, the sealing width 63(B) of the unequal-width cylindrical surface 532 in the a-a section exceeds 50% or more of the thickness 631(t1) of the outer edge of the metal butterfly plate 51, and the sealing width is 4mm or more; the sealing width 63(B) of the unequal-width cylindrical surface 532 in the c-c section exceeds 70% or more of the thickness 631(t1) of the outer edge of the metal butterfly plate 51, and the sealing width is 5.6mm or more; the unequal width cylindrical surface 532 is crimped to the liner inner surface 311 to form a continuous and reliable seal surface 6, and is also connected to the shaft seal surface 637 and the shaft bore surface 634. as shown in fig. 2A and 4C, the largest radius of the seal surface 6 at the C-C cross section also bears the largest static torque, and the largest seal width 63(B) provides a higher pressure-resistant airtight capability, and such seal width 63(B) is not less than the width of the conventional band seal 62.

Referring to fig. 5Ai, 5Aii, and 5Aiii, the composite sealing structure 67 (see fig. 4A to 4D) can satisfy the reasons of low torque and good service life: the contact angle 71(θ) of the unequal-width curved surface 533 in the section a-a is small and the sliding distance is greatly reduced, and the contact angle 71(θ) of the unequal-width curved surface 533 is close to the contact angle 71(θ) of the conventional linear seal.

Referring to FIG. 5Ai, FIG. 5Aii, FIG. 5Aiii, FIG. 5B, FIG. 5C, FIG. 5D and FIG. 5E, the composite seal structure 67 (see fig. 4A to 4D) can satisfy further description of low torque and good service life, the composite seal structure 67 is closed during the a-a section, the unequal-width curve 533 produces the interference sliding 7 with the liner inner surface 311, and the unequal-width curve 533 can slide forward at the sliding angle 74(ψ), the frictional force 75(F) acts on the liner inner surface 311, and forming a packing recess at the packing and a forwardly projecting liner deformation 68 (delta) forward of the butterfly plate outer edge 53, the material of the inner lining surface 311 of the deformed lining 68 (delta) can bear extrusion, the deformation is determined according to the tightening amount 65 (epsilon), and the material of the inner lining surface 311 on the rear side of the outer edge 53 of the butterfly plate can bear tension; the sliding angle 74 (psi) and liner deformation 68 (delta) of the composite seal 67 are smaller than those of the band seal 62 and linear seal 61; the greater the sliding angle 74 (psi) and liner deformation 68 (delta) is, the more the material of inner liner surface 311 and fluoroplastic seal 69 outside butterfly plate 5 is subjected to creep and friction force 75 (F).

Referring to fig. 6, when the butterfly plate 5 is opened or closed, the butterfly plate 5 is opened to a certain degree to form the slit flow channel 81 in the flow channel 8, and then a sudden expansion flow channel 814 and a gradual reduction flow channel 815 are respectively formed on both sides of the butterfly plate 5, as shown by a flow line 811 in the figure, and a backflow region 812 is formed on the back side of the butterfly plate 5 during the flow of the fluid, so that the unequal width curve 533 of the outer edge 53 of the butterfly plate 5 can provide more flow area for the slit flow channel 81, that is, a larger slit width 813(W), which is very helpful to increase the flow rate and Cv value of the butterfly plate 5 at a small angle position, and also can reduce the fluid torque 792 (Th).

The torque required to close the butterfly valve of the invention at one atmosphere is 40Ntm, for example a 3 inch butterfly valve, and is only required at approximately 90 degrees, only <30Ntm from zero degrees to 80 degrees, and only <20Ntm to open, which results in a smooth occurrence of the interference slip 7 experienced by the inner liner surface 311, and a reduction in the experienced friction force 75(F), especially a reduction in the torque required to open, which also represents a substantial reduction in the friction force 75(F) and an increase in the useful life of the butterfly valve 1.

In the test of the embodiment of the invention in the standard test bench, the angles of the butterfly plate 5 are distributed at 0 degree, 18 degrees, 36 degrees, 54 degrees, 72 degrees and 90 degrees, the 0 degree is full-open and 90 degrees is full-closed, the flow coefficient Cv value of the test result is shown in the table one, the Cv value of the tenth reference case is shown in the table two, and the Cv value of the eleventh reference case is shown in the table three; referring to fig. 6Bi, fig. 6Bii, and the curves a, B, and C of fig. 6Biii, the following are the comparative descriptions of the butterfly valve of the present invention and these two references:

1. the linearity of the flow coefficient Cv curve of the butterfly plate is better than that of the reference tenth and eleventh cases.

2. The butterfly plate has a flow coefficient Cv% of 16% at a low opening degree of 36 degrees, a tenth case is referred to as 9% at an opening degree of 35 degrees, and an eleventh case is referred to as 11% at an opening degree of 40 degrees.

3. The butterfly plate has a flow coefficient Cv% of 34% at an opening degree of 54 degrees, a tenth case at an opening degree of 55 degrees Cv% of 23%, and an eleventh case at an opening degree of 60 degrees Cv% of 26%.

Watch 1

Watch two

Watch III

Claims

1. A fluoroplastic butterfly valve structure, comprising: a valve body, a butterfly plate, a liner and a back ring;

2. A fluoroplastic butterfly valve structure as claimed in claim 1 wherein said butterfly plate has said metal butterfly plate and a fluoroplastic package, said fluoroplastic package encasing said metal butterfly plate, said toroidal surface being on said fluoroplastic package, the outer edge of said metal butterfly plate also having a corresponding curved surface configuration, a non-uniform width cylindrical surface and a non-uniform width curved surface, said non-uniform width curved surface having the longest smooth arc line near said valve shaft and the shortest smooth arc line near the center of said butterfly plate, and said non-uniform width curved surface being disposed in the closing rotational direction of said butterfly plate.

3. A fluoroplastic butterfly valve construction according to claim 1 wherein the butterfly plate of a 3 inch butterfly valve is 8mm thick, and wherein the outer edge of the butterfly plate has a seal width of at least 4mm near the valve axis and at least 5.6mm near the center of the butterfly plate.

4. A fluoroplastic butterfly valve construction according to claim 1 wherein the compression ratio of the sealing surface is equal to the ratio of the amount of packing to the thickness of the back ring, the compression ratio being in the range 15% to 20%.

5. A fluoroplastic butterfly valve construction according to claim 1 wherein the butterfly is separated at each end by the raised portion into two butterfly wings, the wings being of plate or cone cross-section.

6. A fluoroplastic butterfly valve construction according to claim 1 wherein the base of the channel is provided with a raised ring having a raised ring height less than the channel depth of the channel to define an expansion space when the back ring is installed in the channel, the raised ring width of the raised ring being between 1.5 and 2 times the thickness of a metal butterfly plate within the butterfly plate but less than the base width of the channel.

7. A fluoroplastic butterfly valve construction according to claim 1 wherein the back ring has an inner diameter substantially equal to the inner diameter of the valve body; the outer diameter of the tubular portion is substantially equal to the inner diameter of the valve body.

8. A fluoroplastic butterfly valve construction according to claim 1 wherein the smooth arcs of the unequal-width curved surfaces are each approximately elliptical.

9. A fluoroplastic butterfly valve structure, comprising: a valve body, a butterfly plate, a liner and a back ring;

10. A fluoroplastic butterfly valve construction according to claim 9 wherein the stiffening portion smoothes the thickness of the corner.

11. A fluoroplastic butterfly valve structure, comprising:

a valve body;

12. A fluoroplastic butterfly valve construction according to claim 11 wherein the toroidal curved surface further comprises a curved surface of unequal width forming a composite seal with the cylindrical surface of unequal width; the unequal-width curved surface extends from the surface of the butterfly plate to the outer edge of the butterfly plate; the smooth arc line of the unequal-width curved surface is in a gradually narrowed shape from the valve shaft to the central part of the butterfly plate, and the unequal-width curved surface is configured in the closing rotation direction of the butterfly plate.